Function detached_allocations 

pub fn detached_allocations() -> usize

Total detached (Gc::new_uncollected) allocations made on this thread since it started. Leak canaries assert a zero delta across embedding scenarios. This counter deliberately lives outside the heap’s own bookkeeping: detached boxes never touch bytes/objects, which is exactly the blind spot that hid issue #249 — a mechanism must not be verified with bookkeeping it maintains itself.